Blood storage temperature telltale



Oct. 21 1958 w. MHUYCK- ETAL BLOOD STORAGE TEMPERATURE TELLTALE Filed April 15, 1957 I 4 Sheets-Sheet 1 FIG. 3;

k nmn mum 4 u u I, I 1 .a a T- 4 4 4 4 M 0 Ma r E 0L WM 6 0 mm me m M I A m M W W u ky , ATTORNEY Oct. 21,1958 w. M. HUYCK IEIAL 2,356,385

spoon STORAGE TEMPERATURE TELLTALE 4 Sheets-Sheet 2 Filed April 15 1957 SUM RF, 0 Tfl0 N M A W0, 0, m mm ATTORNEY v w. M; HUYCK ETAL 2,856,885

. BLOOD STORAGE TEMPERATURETELLTALE Filed April 15, 1957 7 4 Sheets-sheaf i5 I //v VENTORS mum l. 1mm w/lmvr 4. Mil/f0 no 3: I K n ATTORNEY United States Patent 2,856,885 BLOOD STORAGE TEMPERATURE TELLTALE Willard M. 'Huyck, Woodland Hills, and Vincent A. Romito, North Hollywood, Calif.

App ic an April 15, 1 57 e i 29 Claims. Cl. 116-106) This invention relates to a telltale device for use in association with a container for the storage for subsequent use of-human blood or other physiological liquids.

In the handling of supplies of human blood after the blood has been taken from donors, it is customary to collect the blood in more or lessstandardized especially constructed bottles for refrigeration until the blood is to be used. Whole blood must be stored under refrigeration at temperatures below 50 F. and preferably between 39' and 43 F. Whole blood must not be used if it has been frozen, and regardless of the temperature must not be used if stored for more than 21 days. Our invention consists generally in providing a visible indicator or telltale device in association with or inside the blood storage bottle which by change of color in the portion of the device visible above the blood level in the storage bottle will indicate whether or not the particular bottle of blood has ever, since the initial refrigeration, reached a temperature above 50 R, such as during its transportation from the refrigerator to the point of use in a hospital operating room or the like. The tell tale, preferably, will also indicate whether, after once having reached a temperature above 50 F., the blood has again been chilled below the critical temperature, and might therefore apparently be usable (Which it is not).

One object of the invention is to provide a telltale device which may be installed on or in a blood storage bottle and which by its color in the portion visible above a marked level on the bottle or the device indicates whether or not the particular batch of blood has ever, since the initial refrigeration, reached a temperature high enough to make it unsafe for transfusion use. An.- other object is to provide a telltale device for use in association with a blood storage bottle which will indicate that the contents of the bottlehad at some interval reached the critical high temperature at which it would become unsafefor transfusion use and. which had (accidentally or surreptitiously) subsequently been re-chilled to an ostensiblysafe refrigerated condition.

These and other objects are attained by purinvention which will be understood from the tollowing description, reference being made to the accompanying drawings in which:

Fig. 1 is a side elevational view partly in section show.- ing the essential details of a commonly used form of blood storage bottle including our telltale device installed within the bottle; s

Fig. 2 is an enlargedside elevational view partly in section showing a preferred form of our blood storage telltale;

Fig. '3 is a diagrammatic representation of the'several stages involved in the use of the telltale shown in Fig. 2, as in a blood storage bottle;

Fig. 4 is an enlarge d side elevational view partly in section of .a' first alternat ve form ofour invention;

Fig. 5'is a diagrammatic representation ofthe several 2,856,885 Patented Oct. 21, 1958 I z stages involved in the use, -with certain modifying alterrations, of the telltale device shown in Fig. 4;

Fig. 6 is an enlarged side elevational view partly in section-of a second alternative form of our invention;

Fig.7 is a diagrammatic representation of the several stages involved in mouse, with certain modifications, of the telltale shown in Fig. 6; i V i Fig. 8 is an enlarged side elevational view partly in section of a third alternative form of our invention;

Fig. 9 is a diagrammatic representation of the several stages involvedin the use", withcertain modifications, of the telltale device shown in Fig 8 Fig. 10 is aside e'levational View partly in section showing a blood storage bottle similar to Fig. l, in which the telltale'de'vice is fitted into the large stopper of the bottle;-and L I Fig. 11 is a side elevational view partly in section showing the alternative arrangement of fastening the tell: tale to the bloodbottlej V i Referringto the drawings, particularly Fig. 1 a typical conventional blood storage bottle consists of a glass bottle 30 having an inserted rubber stopper 31, and also having near the bottom of the bottle a metal band 32 and 'a bail 33 hingedly attached thereto by which the bottle and contents may be hung in an inverted position, for example' during the removal of the contents in a blood'transfusion operation. The stopper 31 is provided, on'the inside of the bottle, with a needle hole 34 which does notgoentirelythrough the stopper, but which per{ mits the puncturing penetration by a hypodermic needle, or other tube, for w'ithdr'awal ofthe blood. The stopper 31 is also provided witha long glass tube 35 which is mounted in a hole 36 which also does not extend entirely through to the outer-face of the stopper but is puncturabl'e bymeansof a'hypoderrnic' needle or the like in order to allow air toenterthe container when blood is being withdrawn from the-invertedbottle'through the opening 34. The-stopper is further" provided with an indicatorenclosing tube '37- havingfan open end 38 which may extend to or ,above' the outer face of the stopper 31, the lower end 39 of the enclosing tube 37 being closed and extending below a normal blood level line 40 whichis marked onthe upper' side wall of the glass bottle 39. Since in actual use the-level of the blood in the bottle may vary above or-belowthe marked blood line 40, the position of-the telltale is adjustable, as for example by-having-the enclosing tube 37 movable in and out of the bottle stoppento adjust the telltale to the proper level. The-open end 38 ofthe enclosing tube 37 may be pro vided with .a removable stopper 41. The tubular telltaledevice, marked generally 42', is inserted within the transparent enclosing tube 37'for use in indicating temperatures above a selected maximum in the blood stored in the bottle. 1 1

Thepreferred form of our telltale invention is shown in Fig. ,2 and. consists of a closed-end transparent tube 45 which isprovided preferably-with a marker band 43 of opaquesenamel .afirred tothe outer surface, and dividing the tube volume, below the stopper -48,'in half. The band maypover thenentire lower .or rounded-end portion of the tube, or the portion of the tube from the closed end up to the top leveLof the-heavy liquidin the tube may be made opaque,- as for exampleby painting, enameling, or covering it with anopaque shield. A suflicient quantity of a non-solidifying light-colored liquid 46 to fill the tube up to the marker band .43isplaced in the tube 45. The light coloredliquid is indicated as yellow in the drawings. On top of this light-colored liquid 46 is placed an approximately equal. volumeof a non-miscible solidifying liquid 47 which has a distinctive contra-sting c0lor--either an inherent color or by an added dye, for example green.

The tube 45 is provided with a closure 48 which permanently and completely closes the space above the two non-miscible contrasting colored liquids, and prevents leakage of the liquids from the tube. 1

For the light-colored nonesolidifying liquid 46, we prefer to use a liquid polyethylene glycol (such as Carbowax 200" made by Carbide and Carbon Chemical Co), having a specific gravity of 1.12. Glycerol may also be used. Other liquids which are'immiscible. with the solidifying liquid 47, and which do not solidify or volatilize in the temperature range here involved, may be used. I

For the solidifying liquid 47, for use in the whole-blood telltale, we prefer to use Z-undeconone (Eastmans P2209 which has a melting range of 52 to 55 F. and a specific gravity of 0.829. Since this material is white, a contrasting coloring dye (such as Krugers Oil Emerald Green Cone) was dissolved or dispersed in the liquified Z-undeconone, about 5 percent by weight being sufiicient to give a dark green color. Other solidifiable liquids inert to the non-solidifying liquid 46, and which in liquid form have lower specific gravity than the non-solidifying liquid 46, may also be used, such as iso-amyl stearate havlIlg a specific gravity of 0.855 and a melting range of 50 to 59 F.; ethyl myristate having a specific gravity of 0.856 and a melting range of 50 to 54 F.; and n-undecyl alcohol having a melting range of 59 to 63 F. and a specific gravity of 0.829.

In Fig. 3 there is represented diagrammatically the disposition of the telltale elements under various assumed conditions of use. Fig. 2 shows the two liquids in the relative positions which they have initially, with the blood bottle in upright position. Theuse of our indicators requires that the initial chilling of the collected blood shall be with the bottle inverted. When the bottle of blood, with the telltale indicator in place, is inverted, the green liquid 47, because of its lower specific gravity, rises to the rounded end 49 (bottom) of the telltale tube 45, and the light colored liquid 46 fills the space between-the green liquid and the closure 48, as shown in Fig. 3(b). When the blood in the bottle has reached a suitable refrigeration temperature below 50 F., preferably about 39 to 43 F.,.the greenmaterial solidifies, and when the bottle and the telltale are uprighted, Fig. 3(c). and kept refrigerated. the green material 47 remains at the bottom 49. below the blood line 40 of the bottle to which line the bottle has been filled, or below the marker band 43, with only the light-colored non-solidifying liquid 46 being visible above the blood or marker. If the temperature of the blood and the telltale then rises above the melting point of the green liquid 47, this liquid, because of its lower specific gravity, rises to a position above the lightcolored liquid 46, as shown in Fig. 3(d) and becomes visible through the bottle above the level of the blood, or

above the marker band 43. This, of course, indicates that the blood content has been overheated and therefore that the blood should not be used.

If desired, the telltale indicators 42 shown specifically in Fig. 2 may be separately refrigerated in inverted position, and then inserted in the enclosing tube'37 of the blood bottle 30 after the blood contents have been initially chilled below 50 F. The telltale will then indicate when the blood has become heated above the critical temperature as before. as illustrated in Figs.,3(c) and 3(d).

In Fig. l there is shown the modification of our invention in which the telltale tube 45 itself is inserted through the blood bottle stopper 31, theelevation of the dividing boundary between the two liquids 46 and 47, or the marker band 43 being adjustable by moving the tube 45 inwardly or outwardly in the stopper. The positions of the two liquids in the tube 45 under difierent condi tions is the same as described above-under Figs. 3(b), 3(0), and'3(d). I

In the first modified form of our invention shown in Figs. 4 and 5, the telltale tube as before consists at normal temperatures of a heavier light-colored liquid 46 in the rounded end 49 of the tube 45 and an approximately equal amount of the solidifiable green liquid 47 resting on the light-colored liquid and both enclosed in the tube. by a long removable stopper 50 which conveniently may be provided with a cut-off mark 51 at an intermediate. position for purposes to be explained later. The telltale. 42', as shown in Fig. 4, is inserted in the enclosing tube. 37 of the bottle 30, and is positioned relative to the blood level line 40 so that the light-colored liquid 46 is below the top level of the blood in the bottle, and the green.

liquid 47' is visible above the blood level. In Fig. 5(b) there is represented the telltale tube 42 in the position.

corresponding to the inverted bottle. In this position theblood in the bottle, and the telltale, are cooled to a tem-- perature below 50 P. so that the green liquid 47' which.

upon inversion has risen to the rounded end 49' is solidi-- lied, and the light-colored liquid 46' is between the solidi-- fied green material 47 and the removable long stopper 50. Fig. 5(c) represents the telltale device when the bottle is uprighted and is under refrigeration, in which condition the long stopper 50 is pulled out to the cut-01f mark 51 in a manner which admits air in a volume approximately equal to that of either the light-colored liquid 46' or the solidified green liquid 47'. The stopper 50 may be cut off at the cut-elf mark, and the stopper 41 for the enclosing tube 37 is then re-inserted. Fig. 5(a) represents the telltale device in the upright position of the bottle after the blood has warmed up above the temperature at which the greenmaterial 47' melts. The green liquid, because of its lower specific gravity, rises above the light-colored liquid 46', both liquids being below the air space 52. The green liquid 47 then shows above the blood level in the bottle or above the marker band 43', and this indicates that the blood should not be used, having reached too high a temperature for safe use.

It then a person attempted to re-chill the blood in the bottle (assuming that he leaves the bottle in an upright position), the green layer 47 whether liquid or solid, will continue to show above the blood level or the marker band 43' and will continue to indicate that the blood should not be used. If on the other hand he first inverts the bottle (as in the initial chilling) after the liquids 46' and 47' are in liquid condition, the green liquid 47' will rise above the light-colored liquid 46', both being below the air space which now collects in the rounded end 49 of the telltale tube 45'. It now after chilling the blood and telltale to the solidification temperature of the green liquid 47', as shown in Fig. 5(b), the bottle is then inverted, the ingredients are in the position shown in Fig. 5(g), that is, the air is entrapped in the rounded end 45', the green liquid 47 is solidified at an intermediate position above the blood line level or the band 43, and the light-colored liquid 46' is on top of the solidified green 47'; in this position the telltale thus indicates green above the blood level line or marker band 43 and therefore the bottle of blood should not be used. The telltale also discloses, because of the air space below the solidified green material, that the contents of the bottle have been re-- chilled after having previously reached a dangerously high temperature.

In a second alternative form of our invention shown in. Figs. 6 and 7, the light-colored liquid 46", at temperatures.

above the solidification temperature of the green liquid 47", rests in the rounded end 49 of the telltale indicatortube 45" with the green liquid on top of the light colored liquid 46" and showing above the blood line or marker band 43". A long removable stopper 50" is inserted in the tube 45" to enclose the liquids only, with no air space. In Fig. 7(1)) the telltale indicator 42 is shown in the inverted position in which the green liquid 47" fills the rounded end 49", and the light-colored liquid 46" is between the green liquid 47" and the stopper 50". In this position the green liquid 47" is solidified when the bottle line level.0f the bottleor the marker band 43'. :9( b.) shows the. positionof the telltale indicator elements shown in Fig. 9(a).

s and contents are redueed to-. a tel llfi iet-urehelow,50 F. The uprighted position. of the chilled indicator .is shown in Fig.7 (c) withthe solidified greenaliquid ,47" in the bottom with the light-colored liquid .46 resting on it and visible above the'blood lineof the bott1e.orthe marker band 43". In this position the long stopper 50" is removed and amixing liquid 53,.whichmay'be colorless, is injected into the tube 45" above the light-colored liquid -46" in an amount approximately equal tothat ,of the light-colored liquid,46". The stopper 50" is then reinserted. The mixing liquid 53 is of. lighter specific gravity than the light-colored liquid 46" andis immiscible with it and is non-solidifying at the temperatures which are here involved. This mixing liquid consistspreferably of benzol, although other liquids which are non-miscible with the light-colored liquid 46" but are miscible with the solidifiable liquid 47", and which are not solidifiable at the temperatures here involved, may be used, such as for example a hydrocarbon solvent known'as Socal No. 1 having a boiling point range of 240 to 340 F., a further requirement of the mixingliquid '53 being that the mixture 54 of green liquid 4 and mixing liquid 53 cannot be solidified at temperatures normally used in the refrigeration of blood. So long as the telltaleindicator remains in the position shown in Fig. 7(d) with the green liquid 47 solidified below the blood line level or the marker band, 43", and the bottle upright, it indicates that the blood has not been heated after the original chilling. If the contents of the blood bottle become warmed to the temperature of melting of the green liquid 47", this green liquid rises through the light-colored liquid l6 and intermingles with or dissolves in the mixing liquid53, giving a lighter green mixed liquid 54'which then indicates that the blood in the bottle should not be used. If at this point an attempt is madeto invert the bottle and the telltale indicator .45" and againcool the blood below the blood critical temperature, the mixture 54 of mixing'liquid 53 and green liquid-47 is-no longer solidifiable'at the ordinary temperatures of refrigeration (above the actual freezing point of blood); and then if the bottle is uprighted, the mixed liquids54 of the diluted' green color shows above the blood line orthe marker band, indicating not only thatthere has been anattempt to re-cool the previously over-heated blood, but also that the'blood should not be used.

.Still another alternative arrangementfor the telltale is shown in Figs. 8 and'9. In Fig.8 the telltale tube 45" is provided with a replaceable stopper 50", and-substantially equal amounts of the green liquid 47" and the lightcolored liquid .46 are placed in the tube below the stopper, the green liquid 47" showing above the blood Fig.

.46" beingbetween the green liquid :47' and the stopper 50". When the'bloodinthe 'bottle'has beenchilled to the temperature of solidificationof the green liquid" 47" andthe bottleis uprighted, the difierent elements are as The .stopper 50". is then removed and a coil of indicator paper 55 is inserted into the tube 45", the coil being long enough to pass through the liquid light-colored material and rest upon the solidified green material .47' inthe bottom of the'tube. An air space-52" is allowed to remain between the'light-colored liquid and the stopper 50 after the latter is replaced. If now ;the bottle and blood content-warms up to the temperature at which the green material 4 becomes liquified, the liquid green material passes through the light-colored,liquid146' and:makes contact with the indicator paper coil 55 which Fit tpermanently stains green. The ,indicator paper 5 consists of :filterpaper or blotter paper which has been previously-treated with a solution of about 10 parts by weight of ethyl cellulose in 100 parts by .weight of lacquer. solvent,,and ,then dried. Other I .fusion use of theblood. the indicator 42 again reach a temperature at which the green material 47. becomes liquified, the elements arrange themselves in the position shown in Fig. 9(h) .coating materials ,such as evinylite .resins dissolved lac- .quer solvent may be-us'ed, it being necessary .that the the blood, Would'give the arrangement of the elements as shown in .Fig. 9( b.)the air space52' being inthe rounded end 49" of the telltale .tube 45" and with the green material 47 solidified ,between .the air and the light-colored liquid 46". .If the bottle is then uprighted, the rounded end 49" of the tube 45" is filled-with air,

the solidified green material 47" appears above the blood line or the marker band 43" and the light-colored liquid appears above that, with the indicatorpaperSS partly in the solidified green material 4.7 but extending also into the light-colored; liquid 4 6,and showing plainlythat the blood in the bottle has-been re-chilled after it has been heated to a temperature which is dangerous "to thetrans- If the upright blood bottle and with the light-colored liquid 46" at the bottom, the green liquid 47" .resting on ,the light-colored liquid, and with the air space 52" above that, and with the stained green filter paper 55 showing also in the air space. i a

In Fig. .11 is shown another way in which the telltale may be used with a blood storage bottle or other container. The tubular-telltale 42 is attached by means of .a band of adhesive tape 56, on the outside surface ofthe container. The melting temperature of the solidifiable material 47 may be selected to compensate for the timetemperature lag between the contents and'the outside of the container, during the warming.

It will be understood that any of the modifications of our invention shown in Figs. 2 to 9 may be adjustably or non-adjustably mounted in the blood bottle stopper 31, as shown in Fig. 10, or may be attached to the outsid surface of the container, as shown in Fig. 11.

Where the term non-solidifiable is used herein and in the claims, it means that the material is not solidified when cooled to temperatures reached in the normal refrigeration of the blood or other material contained in the storage container.

While our invention has been described in connection with indicating the exposure of whole blood to temperatures above a selected spoilage point, it will be clear that our invention may be applied as telltale devices to indicate other maximum temperatures, selecting the solidifiable liquid with a proper melting point and the nonmiscible non-solidifying liquid in suitable greater specific gravity in relation thereto.

We claim: 1. A telltale device for use with a materialstorage container comprising an elongated transparent tube have a closed inner end; a non-solidifying non-volatile liquid containedin the closed end portion of said tube; a solidifiable liquid contained in said tube above and in contact with said non-solidifying liquid, said solidifiable liquid beinga non-volatile liquid and non-miscible with said non-soliditying liquid, said solidifiable liquid having a lower specific gravity than said non-solidifying liquid, and havinga melting point correspondingtoa critical temperature for the material in said container; and a closure for the open end of said tube, said two liquids being of visually distinguishable. colors.

2. The device defined in claim 1, in which the stored material .is .whole human blood, and the solidifiable ma- .terial is a stable, inert organic chemical composition-nonmiscible with said non-solidifying liquid, and having a melting temperaturein'the range from 50 to 63 F and a specific gravity lower than said non-solidifying liquid.

3. The device defined in claim 1, in which the stored material is whole human blood, and the solidifiable material is selected from the group consisting of Z-undeco- 6. The device defined in claim l, in which the stored material is while human blood, and the solidifiable material is 2-undeconone.

7. The device defined in claim 1, in which the stored material is whole human blood, and the solidifiable material is n-undecyl alcohol.

8. The device defined in claiml, in which, after the solidifiable liquid has been solidified in the closed end portion of said tube, and in upright position, the closure is removable, to admit an air pocket above said liquids, said solidifiable liquid being a stable, inert, organic chemical composition non-miscible Wtih said non-solidifying liquid having a melting temperature in the range from 50 to 63 F., and a specific gravity lower than said nonsolidifying liquid.

9. The device defined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end portion of said tube, and in upright position, the closure is removable, to admit an air pocket above said liquids, said solidifiable liquid being selected from the group consisting of Z-undeconone, iso-amyl stearate, ethyl myristate, and n-undecyl alcohol.

10. The device defined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end portion of said tube, and in upright position, the closure is removable, to admit an air pocket above said liquids, said solidifiable liquid being iso-amyl stearate.

11. The device defined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end portion of said tube, and in upright position, the closure is removable, to admit an vair pocket above said liquids, said solidifiable liquid being ethyl myristate.

12. The device defined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end portion of said tube, and in upright position, the closure is removable, to admit an air pocket above said liquids, said solidifiable liquid being 2-undeconone.

13. The device defined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end portionj'of' said tube, and in upright position, the closure is removable, to admit an air pocket above said liquids, said solidifiable liquid being n-undecyl alcohol.

14. Thedevice defined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end portion of, said tube, and in upright position, the closure is removable, and a quantity of a mixing liquid is injected [into said tube above said non-solidifiable liquid, said mixing liquid being miscible with said solidifiable liquid when it is liquid, to provide a mixed liquid which is not solidifiable at temperatures above the freezing point of whole human blood; said solidifiable liquid being a stable, inert, organic chemical composition non-miscible with said non-solidifying liquid having a melting temperature in the range from 50 to 63 F., and a specific gravity lower than said non-solidifying liquid, and a coloring agent.

15. The device defined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end portion of said tube, and in upright position, the closure is removable, and a quantity of amixing liquid is injected into said tube above said non-solidifiable liquid, said mixing :liquidybeing miscibl'e jwith said solidifiable liquid :when it is liquid, to provide a mixedliquid which is not "solidifiable at temperatures "above the freezing point of 5 whole humanblood;said solidifiable liquid being selected from the group Iconsisting of .2-undeconon'e, iso-amyl stearate, ethyliinyristate, and undecyl alcohol.

16;"The device defined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end portion. of said tube, and in upright position, the closure is removable, and a quantity of a mixing liquid is injected into said tube above said non-solidifiable liquid, said mixing liquid being miscible with said solidifiable liquid when'it is liquid, to provide a mixed liquid whch is not solidifiable at temperatureis above the freezing point of whole human blood; said' solidifiable. liquid being isoamyl stearate and a coloring agent.

17. The device defined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end portion of said tube,'and' in upright position, the closure is removable, and a quantity of a mixing liquid is injected into said tube abovesaid non-solidifiable liquid when it is liquid, to provide a mixed liquid which is not solidifiable at temperatures above the freezing point of whole human blood; said solidifiable liquid being ethyl myristate and a coloring agent. i 1

18. The device defined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end m portion of said tube, and in upright position, the closure isremovable, aiid a quantity of a mixing liquid is injected into said tube above said non-solidifiable liquid, said mixing liquid being miscible with said solidifiable liquid when it is liquid, to provide a mixed liquid which is not solidifiable at temperatures above the freezing point of whole human blood; said solidifiable liquid being Z-undeconone and a coloring agent. i

' 19. The device defined in claim 1, in which, after the solidifiable liquid has beensolidified in the closed end m portion of said tube, and in upright position, the closure is removable, and a quantity of a mixing liquid is injected into said tube above said non-solidifiable liquid, said mixing liquid being miscible with said solidifiable liquid when it is liquid, to provide a mixed liquid which is not 5 solidifiable at temperatures above the freezing point of cator paper being stainable only by said solidifiable liquid when in liquid condition, said solidifiable liquid being a stable, inert, organic chemical composition non-miscible with said non=solidifyiug liquid having a melting temperature in the range from 50 to 63 F., and a specific 6O gravity lower than said non-solidifying liquid, and a coloring agent.

22. Thedevicedefined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end of said tube, and in upright position, the closure is remov- 65 able, an air pocket is admitted above said liquids, and

.an indicator paper strip is inserted into said tube, said indicator paper being stainable only by said solidifiable liquid when in liquid condition, said solidifiable liqud having a coloring agent dispersed therein and being se- 0 lected from the group consisting of Z-undeconone, isoamyl stearate, ethylmyristate and n-undecyl alcohol.

23. The device defined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end of said tube, and in upright position, the closure is removable, an air pocket is admitted abovefsaid liquids, and,

an indicator paper strip is inserted into said tube, said indicator paper being stainable only by said solidifiable liquid when in liquid condition, said solidifiable liquid being iso-amyl stearate and a coloring agent.

24. The device defined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end of said tube, and in upright position, the closure is removable, an air pocket is admitted above said liquids, and an indicator paper strip is inserted into said tube, said indicator paper being stainable only by said solidifiable liquid when in liquid condition, said solidifiable liquid being ethyl myiistate and a coloring agent.

25. The device defined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end of said tube, and in upright position, the closure is removable, an air pocket is admitted above said liquids, and an indicator paper strip is inserted into said tube, said indicator paper being stainable only by said solidifiable liquid when in liquid condition, said solidifiable liquid being Z-undeconone and a coloring agent.

26. The device defined in claim 1, in which, after the solidifiable liquid has been solidified in the closed end '10 of said tube, and in upright position, the closure is re' movable, an air pocket is admitted above said liquids, and an indicator paper strip is inserted into said tube, said indicator paper being stainable only by said solidifiable liquid when in liquid condition, said solidifiable liquid being n-undecyl alcohol and a coloring agent.

27. The device defined in claim 21, in which the paper indicator comprises a porous paper strip coated with a coating material soluble in said solidifiable liquid but not soluble in said non-solidifying liquid.

28. The device defined in claim 1, in which a marker band is provided on said tube to define the boundary between said solidifiable liquid and said non-solidifiable liquid.

29. The device defined in claim 1, in which the portion of said transparent tube initially containing said nonsolidifying liquid is opaque.

References Cited in the file of this patent UNITED STATES PATENTS 2,662,018 Smith Dec. 8, 1953 

1. A TELLTALE DEVICE FOR USE WITH A MATERIAL STORAGE CONTAINER COMPRISING AN ELONGATED TRANSPARENT TUBE HAVE A CLOSED INNER END; A NON-SOLIDIFYING NON-VOLATILE LIQUID CONTAINED IN THE CLOSED END PORTION OF SAID TUBE; A SOLIDIFIABLE LIQUID CONTAINED IN SAID TUBE ABOVE AND IN CONTACT WITH SAID NON-SOLIDIFYING LIQUID, SAID SOLIDIFIABLE LIQUID BEING A NON-VOLATILE LIQUID AND NON-MISCIBLE WITH SAID NON-SOLIDIFYING LIQUID, SAID SOLIDIFIABLE LIQUID HAVING A LOWER SPECIFIC GRAVITY THAN SAID NON-SOLIDIFYING LIQUID, AND HAVING A MELTING POINT CORRESPONDING TO A CRITICAL TEMPERATURE FOR THE MATERIAL IN SAID CONTAINER; AND A CLOSURE FOR THE OPEN END OF SAID TUBE, SAID TWO LIQUIDS BEING OF VISUALLY DISTINGUISHABLE COLORS. 